1. Field of the Invention
The present invention relates to a monitor (surveillance) camera system comprising a monitor camera and a method of controlling a photographing direction of the monitor camera, and more particularly to a monitor camera system and photographing direction controlling method, which are capable of easily facing the monitor camera toward a desired direction through remote manipulation or control.
2. Description of the Related Art
So far, a monitor camera in which a camera and a rotatable table therefor are placed in a dome-like housing has been put on the market. This monitor camera is called a “compound camera” because of the camera being capable of, through movements of the rotatable tables, rotating horizontally (pan) while rotating vertically (tilt). The compound camera can rotate through 360 degrees without limitation in the pan directions, while rotating in an angular range between 0 degree and 90 degrees, that is, from a horizontal direction to a vertical direction, in the tilt directions. In addition, through the manipulation of a controller, this compound camera can take a photograph at a desired angle or in a desired direction in a state installed on a ceiling of public facilities or the like. Still additionally, even if a target subject passes right under it, as FIG. 14 shows, immediately a camera 10 turns to right under, it can rotate 180 degrees around a lens thereof to chase the target subject continuously, thus providing pictures throughout a monitoring area.
FIG. 12 is an illustration of a state in which a controller 12 for controlling a compound camera 11 and a monitor 13 for displaying a picture taken through the compound camera 11 are connected through a coaxial cable 16 to the compound camera 11. The controller 12 functions as a control element and comprises a joystick 14 and a numeric pad (numeric keys) 15.
This compound camera 11 is designed so that a plurality of camera positions, for example, taking a direction to an entrance, a direction to an exit and a direction to a window, are preset in the controller 12 in the form of identification numbers (ID). After preset, simply by inputting the ID corresponding to a camera position through the use of the numeric pad 15, the camera can be turned to follow the preset direction.
In addition, the joystick 14 of the controller 12 is manipulated for controlling the moving (rotating) speed of the camera 11. When the joystick 14 is tilted, as shown in FIG. 13, the camera 11 rotates in a tilting direction at a speed proportional to the movement component of the joystick 14 in the vertical-axis direction and rotates in a panning direction at a speed proportional to the movement component thereof in the horizontal-axis direction. An operator checks pictures while viewing the monitor 13 and, when the rotating camera 11 catches a desired direction, the operator returns the joystick 14 to the neutral position to stop the rotation thereof in the tilting and panning directions.
Meanwhile, a group including the inventors of the present invention has developed a new compound camera capable of limitlessly rotating 360 degrees in panning directions while rotating 180 degrees in tilting directions. This compound camera can provide the increased degree of freedom in moving direction and, hence, is capable of moving promptly to the target camera position through the shortest path. In addition, this compound camera can set the field angle in the zoom-up condition at approximately two degrees to allow an enlarged display of a local area.
However, when a camera has a high zooming ability, difficulty is encountered in understanding what place a picture displayed shows. Therefore, in a case in which there is a need to align the camera in a specific direction through the use of a joystick of a controller, difficulty is experienced in understanding the direction the camera is to be aligned in, that is, the joystick tilting direction, by viewing only a zoomed picture appearing on a monitor.
In this case, in general, the camera is released from its zooming condition to display a picture with a standard field angle on the monitor for confirming the present photographing direction from that picture, before the joystick is manipulated to implement the camera speed control. However, this procedure tends to take much time, and is undesirable, for example, in the case of facing the camera toward a place in which an abnormal situation has occurred.